1. Field of the Invention
This invention relates to the improvements in a piston for a piston pump.
2. Description of the Prior Art
Generally speaking, a piston of a piston pump, particularly of a high pressure piston pump receives a high pressure. Due to such a high pressure, a piston packing is forced out of the piston member or easily worn out. Consequently, friction of the piston member relative to a cylinder increases, thus accelerating breakage of the piston member or the cylinder, and reducing airtightness therebetween as the packing is worn, resulting in the failure of the parallel reciprocating stokes of the piston within the cylinder.